This invention relates generally to turbomachines and, more particularly, to retaining means for blades therein.
Retention of aerodynamic blades within the periphery of a turbomachinery rotor or disk has long been a problem in the industry. The most common method of retaining blades within the disk is by the combination of dovetailed blades and axial slots in the periphery of the disk. This method has been found to be quite satisfactory and desirable for purposes of withstanding the radial loads caused by centrifugal force. However, since there are considerable axial forces on the blades, there is a necessity to provide for axial retention thereof in both directions. In this connection, it is desirable to minimize weight, windage and stress concentrations while providing a positive retention means which is simple and relatively easy to assemble and disassemble. That is, for maintainability and repair purposes, it should be relatively easy to remove and replace a single blade which may be damaged by a foreign object or the like.
Historically, axial blade retainers have been secured to the disk by way of a plurality of circumferentially spaced bolts. This approach is undesirable for a number of reasons including increased windage and air temperature caused by the protruding bolt heads or nuts, the existence of stress concentrations at the bolt holes, and the difficulty and time of assembly and disassembly.
In recognition of these problems, a boltless blade retainer was devised as shown and described in U.S. Pat. No. 3,768,924, issued to Robert J. Corsmeier et al and assigned to the assignee of the present invention. Although this approach offers significant improvement in the characteristics mentioned above, the increased demand in the industry for improved cyclic life capabilities calls for further improvements. Since the design loads, operating environment and material capability are all essentially fixed, life improvements must be achieved by streamlining the design and reducing stress concentrations in life limiting areas.
It is therefore an object of the present invention to provide an improved boltless blade retainer.
Another object of the present invention is the provision in a disk and blade retainer combination for improved cyclic life capabilities.
Another object of the present invention is the provision in a blade retainer apparatus for reduced stress concentrations in life limiting areas.
Still another object of the present invention is the provision for a blade retainer apparatus which is easy to assemble and effective in use.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.